# InChIKey¶

The International Chemical Identifier Key (InChIKey) of a material is derived from the InChI. It is a 27 character non-human readable condensed digital representation of the InChI, also known as a hash.1

## Notation¶

The InChIKey is a 14-8-1 character string. The first 14 characters represent the connectivity and charge information. The next 8 character represent the remaining sublayer information. The final character represents the kind of InChIKey being generated, including the version of InChI used.

The 14-8-1 Character string is represented as follows:

 1 XXXXXXXXXXXXXX-YYYYYYYYFV-P 

### Examples¶

#### Methane (CH4)2¶

InChIKey: VNWKTOKETHGBQD-UHFFFAOYSA-N

 1 2 3 4 5  H 0.5288 0.1610 0.9359 C 0.0000 0.0000 0.0000 H 0.2051 0.8240 -0.6786 H 0.3345 -0.9314 -0.4496 H -1.0685 -0.0537 0.1921 

#### Water (H2O)3¶

InChIKey: XLYOFNOQVPJJNP-UHFFFAOYSA-N

 1 2 3 H 0.7493682 0.0000000 0.4424329 O 0.0000000 0.0000000 -0.1653507 H -0.7493682 0.0000000 0.4424329 

## Schema¶

The JSON schema and an example representation for this property can be found here.